Heating apparatus



July 23, 1946.

S. J. BUDLAN E HEATING APPARATUS Filed Oct Patented July 23, 1946 HEATING APPARATUS Stanley J. Budlane, Chicago, Ill., assigner to Stewart-Warner Corporation, Chicago, Ill., a corporation of Virginia Application October 23, 1942, Serial No. 463,059

7 Claims. 1

My invention relates to heating apparatus, and more particularly to heating apparatus of the internal combustion type.

In heating apparatus of the internal combustion type, and especially in heating apparatus designed for use in aircraft and for similar purposes, the muier is located in the heat transfer means to guide the products of combustion to this heat transfer means and to absorb sound created in the operation of the heater.

An object of my invention is to provide heating apparatus having a new and improved muiiler.

Another object of my invention is to provide heating apparatus of the internal combustion type and having a new and improved muiiler which facilitates the now of the products of combustion from the combustion chamber to the heat transfer means.

Another object of my invention is to provide new and improved heating apparatus wherein sound absorbing material in the muier is protected against melting under the temperature produced in the combustion chamber.

Another object of my invention is to provide new and improved heating apparatus having superior means for directing the flow of gases therethrough and for protecting the muiller against the intense heat created in the combustion chamber.

Another object of my invention is to provide a new and improved muiler.

Other objects and advantages will become apparent as the description proceeds.

In the drawing:

Fig. 1 is a view showing a longitudinal section through a heater embodying a preferred form of my invention; and

Fig. 2 is a View showing a transverse section through the nose of the muiller, and is taken along the irregular line 2-2 of Fig. 1.

The heating apparatus disclosed in the drawing comprises a combustion chamber IIJ to which a combustible mixture is supplied through the ports I2 in a burner tube I4 in communication with one end of a Venturi tube I6. Fuel or a rich mixture of fuel and air is supplied to the throat of the Venturi tube I6 by a fuel supply pipe I8 having outlet openings 20 in the restricted throat of the Venturi tube I6. A heater inlet 22 is supplied with air from a ram, blower or other suitable supply means, and part of this air enters the open end 24 of the Venturi tube I6 and forms a combustible mixture with the fuel supplied by the pipe I8.

The combustion chamber I is provided With one or more electrical igniters 26 for initially igniting the combustible mixture supplied to the combustion chamber l0. It will be understood that these igniters may be controlled by the usual thermostatic switch which disconnects these igniters from their source of electrical current when the heater attains normal operating temperature. Thereafter, combustion is maintained by the reigniter 28 and also by the ring of burning gases which collect in the annular corner 30 of the combustion chamber I0.

The combustion chamber l0 is located in one end of a tubular heat transfer means or heat exchanger 32, which is illustrated as having hollow fins extending lengthwise thereof. A muilier 34 is located in the heat exchanger 32 and cooperates therewith to direct the hot gases, which constitute the products of combustion, into the longitudinal passages 36 formed in the hollow fins. As these gases flow lengthwise of the hollow iins, the gases give up their heat to the heat exchanger 32 and the cooled gases are discharged from the left-hand end of the passages 36 into an outlet chamber 38 formed between the left-hand end of the muiiler 34 and a plate 4i), which closes the left-hand end of the tubular heat exchanger 32. An outlet fitting 42 is mounted in the plate 4B and has a passage 44 connecting the outlet chamber 38 with any suitable exhaust pipe connected to the threaded end 46 of the fitting 42. i

The heat exchanger 32 is surrounded by a cylindrical casing 48 which cooperates with the heat exchanger to form longitudinal Ventilating air ducts between the hollow ns. A sheet metal cone 50 connects the heater inlet 22 with the inlet end of the casing 48, so that the Ventilating air is supplied to this casing by the same ram or blower which furnishes the air for the combustible mixture. The left-hand or outlet end of the casing 48 may open directly into the aircraft cabin or other space to be heated, or may be connected to ducts for directing the heated Ventilating air t0 selected locations,

The products of combustion flowfrom the combustion chamber ID to the hollow fins by way of an annular tapered passage 52 formed between the tapered nose 54 of the muiiler 34 and the adjacent portion of the tubular heat exchanger 32. This tapered nose terminates in a cap 56 which is directly exposed to the burning gases in the combustion chamber I0 and which cooperates with the rest of the tapered nose smoothly and easily to direct the hot products of combustion from the combustion chamber to the interiors of the hollow hns.

The muflier, in general, comprises a sheet metal shell 58 containing a quantity of sound absorbing material 66, such as glass wool or stainless steel wool. The shell 58 is provided with a plurality of small openings 62 which connect the interior of the muiller shell with the gas passages in the hollow fins and form acoustic couplings through which sound in the gases of combustion may ow into the interior of the mufller and be absorbed by the glass wool or stainless steel wool therein.

While the glass wool or stainless steel wool is heat resistant to a considerable degree, this material might melt or be softened if exposed for long periods of time to the intense heat created in the combustion chamber i Si. The muffler shell 58, therefore, terminates in an end 64, which is separated from the cap 5% by an air or gas space 56 that serves to insulate the glass wool or stain less steel wool from the heat in the combustion chamber Hl. This space 6B also constitutes a resonance chamber which is acoustically coupled to the interior of the shell 58 by an annular series of openings 53 located in the end lill of this shell,

The mullier shell 58 and heat exchanger 32 are preferably made of thin sheets of stainless steel or other suitable material, and the cap or gas deflector plate 56 may be made of the same material or of more heat resistant material such nichrome. This cap may be welded or otherwise suitably secured to the tapered end of the muiller shell and constitutes a unitary part of the muiller structure.

From the foregoing description it will be apparent that in my new and improved heater, the muliler is provided with a gas or air space which insulates and protects the sound absorbing material of the muflier from the intense heat in the combustion chamber. This heat insulating space, acting as a resonance chamber, cooperates with and assists the sound absorbing material in rendering the operation of the heater quiet and substantiallv silent. The combination insulating and resonance chamber is formed between a beat resistant cap attached to the end of the muflier shell proper, and this cap cooperates with the tapered end of the muiiler shell to deiiect and direct the gases of combustion from the combustion chamber to the longitudinal passages in the hollow of the heat exchanger.

The heating apparatus which I have illustrated and described may be made extremely compact and of light weight for a given heat output, and is particularly adapted for use in aircraft and for other similar purposes. My novel heating apparatus. however, is not limited to such use and is eoually well adapted for other uses wherein the conditions are entirely diierent from those encountered in aircraft operation. Because of the improved silencing effect of my invention, heating apparatus embodying this invention is substantially noiseless and may be utilized in locations where quietness of operation is of prime importance.

While I have illustrated and described only a single embodiment of my invention, my invention is not limited to the details shown and described. but may assume numerous other forms, and my invention is to be construed as including all variations and modications falling within the scope of the appended claims.

I claim:

1. Heating apparatus comprising a tubular heat exchanger having hollow fins extending lengthwise thereof, means forming a combustion chamber located in one end of said tubular heat exchanger, means for supplying a combustible mixture to said combustion chamber, a muiller 10- cated in said heat exchanger and containing sound absorbing material, a sheet metal shell providing an air space interposed between said combustion chamber and said sound absorbing material and forming a heat insulating barrier between said combustion chamber and said material, and means for directing Ventilating air over said heat exchanger.

2. Heating apparatus of the class described comprising a tubular heat exchanger, means for supplying hot products of combustion to one end of said heat exchanger, a muffler located in said heat exchanger, said muiiler having a hollow shell containing sound absorbing material, said shell having openings providing communication between the interior of said shell and the interior of said heat exchanger, means providing a res= onance chamber at one end of said muiler in position to receive said hot products of combustion thereon and acoustic couplings between said resonance chamber and the interior of said muiiler shell, and means for supplying Ventilating air to the exterior of said heat exchanger.

3. Heating apparatus of the class described comprising means forming a combustion chamber, heat transfer means receiving products of combustion from said combustion chamber, a muiller located in said heat transfer means, said muiller comprising a shell having a tapered end, sound absorbing material in said shell, means providing communication between the interior of said shell and the interior of said heat transfer means, and a cap attached to said shell and cooperating therewith to form a heat insulating and sound resonance chamber interposed between said combustion chamber and said sound absorbing material.

fl. In heating apparatus of the class described, the combination of a combustion chamber, means for supplying means forming a combustible mix ture thereto, heat transfer means receiving the products of combustion from Said combustion chamber, a muiiler located in said heat transfer means, said muiiler including a pair of acoustically coupled chambers arranged with one chamber between the other chamber and said combustion chamber and sound absorbing material in the other one only of said chambers, and means for directing Ventilating air over said heat transfer means.

5. Heating apparatus of the class described comprising tubular heat transfer means, means forming a combustion chamber for supplying products of combustion to one end of said heat transfer means, a muiller located in said heat transfer means and cooperating therewith to form passages for the hot products of combustion, said muiiler having a tapered end terminating in a rounded gas deflecting cap for directing flow of hot products of combustion toward said heat transfer means, said cap cooperating with other parts of said muliler to provide a combination heat insulating and resonance chamber, said muiiler including sound absorbing material protected by said second named chamber against extreme temperatures created in said combustion chamber, and means for supplying a combustible mixture to said combustion chamber.

6. A muiiler for a heater having a tubular heat exchanger and means for supplying hot gases to one end of said heat exchanger, said muiiler comprising a perforated sheet metal shell containing a quantity of sound absorbing material. and a rounded cap attached to one end of said shell and cooperating therewith to form an insulating chamber for protecting said sound absorbing material from hot gases flowing past the cap to the shell when the muier is inserted in said tubular one end of said heat exchanger, a perforated shell 10 containing a quantity of sound absorbing material and a cap attached to a perforated end portion of said shell and cooperating therewith to form a resonance chamber adapted to protect the sound absorbing material from hot gases flowing past the cap to the shell When the muflier is inserted in said tubular heat exchanger with said cap adjacent said means for supplying hot gases.

STANLEY J. BUDLANE.

Certificate of Correction Patent No. 2,404,617. July 23, 1946. STANLEY J. BUDLANE It is hereby certified that error appears in the printed speeiiication of the above numbered patent requiring correction as follows: Column 4, line 42, claim 4, strike out the Words means forming and insert the same after of and before a in line 41, same claim; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of October, A. D. 1946.

LESLIE FRAZER,

First Assistant 'ommz'sszoner of Patents. 

